DAMB 721 Microbiology Final Exam - A 200 points Your name (Print Clearly): _____________________________________________ I. Multiple Choice: In the blank to the left of each question, place the letter corresponding to the ONE BEST answer. _____ 1. The HIV surface glycoprotein that binds to the CD4 receptor is: 1?? A. gp 160 B. gp 41 C. gp 120 D. HTLV III _____ 2. The E. coli fur gene: A. is regulated by temperature and pH B. is regulated by iron concentration C. codes for the production of siderophores D. codes for the production of a Shiga-like toxin E. b and c are correct F. b and d are correct G. all but a are correct _____ 3. The first phagocytic cell to respond to microbial invasion is: A. monocyte B. macrophage C. polymorphonuclear neutrophil D. GALT macrophages E. histiocytes ____ 4. Form of gene transfer in which either a fragment of DNA or a plasmid from the donor bacterium is transferred across the cell membrane of the recipient bacterium independently of a virus or pilus: A. conjugation B. transduction C. transformation D. locomotion _____ 5. Gram negative cells: A. when Gram stained, will be red because crystal violet is washed out of the cell with alcohol B. when Gram stained, will be blue because they retain crystal violet C. are the only bacterial cell type with peptidoglycan D. are the only bacterial cell type with an outer membrane containing lipopolysaccharide E. a and d are true ______ 6. In regards to the normal bacterial flora: A. The host would be better off without them. B. In general, they are present at a particular body site for brief periods of time. 2?? C. They actually prime the host immune system. D. By releasing bacteriocins and other antimicrobials they provide a barrier to colonization by exogenous bacteria. E. c and d are true F. all but a are correct ______ 7. A specific example of bacterial tissue tropism as it occurs in the oral cavity A. the Actinomyces viscosus Type 1 and Type 2 adhesins B. the invasins produced by Mycobacteria and Salmonella spp. C. margination followed by diapedesis D. chemotaxis towards the C5a complement component _____ 8. Phagocytic leukocytes are chemotactic to these bacterial products: A. fmet-LEU-PHE B. muramyl-dipeptide C. the C5a complement component D. a and b are correct E. a, b, and c are correct _______ 9. Penicillin is an effective bactericidal antimicrobic because: A. it has a molecular structure similar to para-amino-benzoic acid B. it interferes with DNA synthesis C. a peptidoglycan synthetic enzyme mistakes the beta-lactam ring for alanine D. it binds to the 30S ribosomal subunit and inhibits protein synthesis _______ 10. When using a chemical agent to disinfect instruments that may be coated with pus or sputum, a detergent or other surfactant such as Tween-80 might be added to the chemical agent in order to ensure: A. proper contact time between the instrument and the chemical agent B. that the chemical agent will have direct contact with microorganisms in sputum or puss C. proper pH of the disinfecting chemical agent D. that the chemical agent will remain in solution in dry climates 3?? _______ 11. The most dangerous pathogens that cause cross-infections in dentistry are those which: A. survive drying for long periods of time and have a long incubation period B. are transmitted by direct contact with lesions C. have a low infective dose D. are shed through desquamation _______ 12. Dental equipment that is reusable and that penetrates tissue, bone or pulp: A. should be disinfected with a high level disinfectant B. should be disinfected with a low level disinfectant C. should be sterilized D. should only be cleaned in an ultrasonicator _______ 13. Barrier protection is recommended: A. for use only when treating patients infected with blood borne pathogens B. for the dentist only; the assistants are not at risk C. to protect the dental staff against aerosols of blood borne pathogens D. to prevent injury if you crash your bike ______ 14. According to the OSHA Bloodborne Pathogens Standard the owner of a dental office will be required to: A. Maintain medical records on their employees B. Provide Hepatitis B vaccinations free of charge C. Examine employees regarding past exposure to HIV and Hepatitis B D. Train employees regarding their occupational risk for blood borne pathogens E. all of the above F. all but c are correct _____ 15. Which streptococcus is not commonly found in dental plaque? A. S. mutans B. S. pyogenes C. S. sanguis D. S. oralis E. S. mitis 4?? _____ 16. Which of the following is not a member of the mutans streptococci? A. S. gordonii B. S. cricetus C. S. sobrinus D. S. mutans E. S. macacae _____ 17. Acidoduric defines this property of bacteria: A. prolific acid production B. metabolism of intracellular carbohydrate C. the ability to survive at pH 5.5 and below D. the ability to survive and metabolize at pH 5.5 and below E. the ability to inhibit acid diffusion ____ 18. There is experimental evidence that, as a smooth surface on a tooth progresses to a carious lesion, the ratio of ___________________ to __________________ will approach 5. A. mutans streptococci to S. salivarius S. mutans to S. gordonii C. S. mutans to S. sanguis A. viscosus to S. sanguis S. mutans to S. salivarius _____ 19. The water insoluble glucan that is the matrix for dental plaque is produced by S. mutans through: A. fructosyl transferases B. glucosyl transferases that catalyze an α-1,3-bond C. glucosyl transferases that catalyze an α-1,6-bond D. invertase _____ 20. The viridans streptococcus that is prevalent in dental plaque and in bacteremias of patients with bacterial endocarditis. A. S. gordonii B. S. agalactiae C. S. sanguis D. S. pyogenes 5?? _____ 21. Cervicofacial actinomycosis can result from the contamination of a surgical site or from trauma involving explanted endogenous organisms. What is not characteristic of this lesion? A. granulomatous inflammation B. healing with scarring C. "sulfur granules" D. formation of interconnecting sinus tracts E. fungal infection ______ 22. The primary virulence mechanism for and the reason no effective vaccine has been developed against diseases caused by Neisseria gonorrhoea is: A. LOS B. oxidase C. the endospore D. the polysaccharide capsule E. antigenic variation ______ 23. A primary virulence factor which is also the primary antigen in diseases caused by Neisseria meningitidis is: A. LOS B. oxidase C. the endospore D. the polysaccharide capsule E. antigenic variation ______ 24. Lecithinases (phospholipases) are toxic, membrane destroying enzymes. One of these is an important virulence factor for: A. Bacillus anthrasis B. Clostridium perfringens C. Corynebacterium diphtheriae D. Mycobacterium tuberculosis E. Salmonella typhi ______ 25. In which of the following diseases does the bacterial agent produce neither an exotoxin nor an endotoxin? A. anthrax B. cholera C. gas gangrene D. typhoid fever E. tuberculosis 6?? ______ 26. The botulinum, tetanus and diphtheria toxins have the following in common: A. they are proteins comprised of two subunits; the largest subunit binds the toxin receptor while the smaller subunit is the toxic component B. they are neurotoxins C. to be activated they must be nicked by a protease and their disulfide bonds must be reduced D. they are released in the presence of a 500 kDa progenitor toxin E. Both A and C are correct _______ 27. The granulomatous lesion that is characteristic of tuberculosis: A. is produced by a delayed type hypersensitivity B. is mediated by helper (CD4) T lymphocytes and cytotoxic (CD8) T lymphocytes C. is a tubercle D. may harbor dormant M. tuberculosis for decades E. All of the above are true. ______ 28. The form of tuberculosis in which patients are actively shedding M. tuberculosis and therefore are most infectious: A. secondary or active tuberculosis B. primary tuberculosis C. miliary tuberculosis D. latent/dormant tuberculosis E. post healing ______ 29. The most important factor in the transmission of the diseases caused by Clostridia and Bacillus spp. is: A. their Gram reaction and cell morphology B. the ability to produce protein toxins C. their oxygen requirement D. the ability to produce endospores E. the ability to cause disease in animals _______ 30. Streptococcus mutans is an etiological factor in dental caries for all of the following reasons except: 7?? A. glucosyltransferases produce glucans B. acidoduric C. acidogenic D. proteases degrade the protein fraction of enamel E. SpaA binds salivary pellicle ______ 31. Which of the following diseases are caused by spirochetes? A. coccidioidomycosis and blastomycosis B. thrush, athletes foot and ringworm C. lyme disease, syphilis and relapsing fever D. typhus and rocky mountain spotted fever ______ 32. An oral manifestation of congenital syphilis is: A. Hutchinson's teeth B. oral chancre C. thrush D. gingival stomatitis ______ 33. An extremely infectious manifestation of primary syphilis is: A. Hutchinson's teeth B. oral chancre C. thrush D. gingival stomatitis _____ 34. Which of the following is not characteristic of Chlamydia ? A. two-stage life cycle B. ability to grow in vitro in ordinary broth media C. causes blindness D. elementary body is infectious ______ 35. An oral infection caused by Candida albicans that results from preventing contact of the maxillary mucosa with saliva: A. denture induced stomatitis B. oral thrush C. angular chelitis D. midline glossitis 8?? _______ 36. What pathogenic fungus is characterized by a large polysaccharide capsule? A. Histoplasma capulatum B. Blastomyces dermatitidis C. Cryptococcus neoformans D. Coccidioides immitis _______ 37. A dimorphic fungus that produces a lesion that resembles a tubercle: A.